Risk of developing active tuberculosis following tuberculosis screening and preventive therapy for Tibetan refugee children and adolescents in India: An impact assessment.

BACKGROUND: Tuberculosis (TB) rates among Tibetan refugee children and adolescents attending boarding schools in India are extremely high. We undertook a comprehensive case finding and TB preventive treatment (TPT) program in 7 schools in the Zero TB Kids project. We aimed to measure the TB infection and disease burden and investigate the risk of TB disease in children and adults who did and did not receive TPT in the schools. METHODS AND FINDINGS: A mobile team annually screened children and staff for TB at the 7 boarding schools in Himachal Pradesh, India, using symptom criteria, radiography, molecular diagnostics, and tuberculin skin tests. TB infection (TBI) was treated with short-course regimens of isoniazid and rifampin or rifampin. TB disease was treated according to Tibetan and Indian guidelines. Between April 2017 and December 2019, 6,582 schoolchildren (median age 14 [IQR 11-16] years) and 807 staff (median age 40 [IQR 33-48] years) were enrolled. Fifty-one percent of the students and 58% of the staff were females. Over 13,161 person-years of follow-up in schoolchildren (median follow-up 2.3 years) and 1,800 person-years of follow-up in staff (median follow-up 2.5 years), 69 TB episodes occurred in schoolchildren and 4 TB episodes occurred in staff, yielding annual incidence rates of 524/100,000 (95% CI 414-663/100,000) person-years and 256/100,000 (95% CI 96-683/100,000) person-years, respectively. Of 1,412 schoolchildren diagnosed with TBI, 1,192 received TPT. Schoolchildren who received TPT had 79% lower risk of TB disease (adjusted hazard ratio [aHR] 0.21; 95% CI 0.07-0.69; p = 0.010) compared to non-recipients, the primary study outcome. Protection was greater in recent contacts (aHR 0.07; 95% CI 0.01-0.42; p = 0.004), the secondary study outcome. The prevalence of recent contacts was 28% (1,843/6,582). Two different TPT regimens were used (3HR and 4R), and both were apparently effective. No staff receiving TPT developed TB. Overall, between 2017 and 2019, TB disease incidence decreased by 87%, from 837/100,000 (95% CI 604-1,129/100,000) person-years to 110/100,000 (95% CI 36-255/100,000) person-years (p < 0.001), and TBI prevalence decreased by 42% from 19% (95% CI 18%-20%) to 11% (95% CI 10%-12%) (p < 0.001). A limitation of our study is that TB incidence could be influenced by secular trends during the study period. CONCLUSIONS: In this study, following implementation of a school-wide TB screening and preventive treatment program, we observed a significant reduction in the burden of TB disease and TBI in children and adolescents. The benefit of TPT was particularly marked for recent TB contacts. This initiative may serve as a model for TB detection and prevention in children and adolescents in other communities affected by TB.

High Prevalence of Active and Latent Tuberculosis in Children and Adolescents in Tibetan Schools in India: The Zero TB Kids Initiative in Tibetan Refugee Children.

BACKGROUND: Tuberculosis (TB) prevalence is high among Tibetan refugees in India, with almost half of cases occurring in congregate facilities, including schools. A comprehensive program of TB case finding and treatment of TB infection (TBI) was undertaken in schools for Tibetan refugee children. METHODS: Schoolchildren and staff in Tibetan schools in Himachal Pradesh, India, were screened for TB with an algorithm using symptoms, chest radiography, molecular diagnostics, and tuberculin skin testing. Individuals with active TB were treated and those with TBI were offered isoniazid-rifampicin preventive therapy for 3 months. RESULTS: From April 2017 to March 2018, we screened 5391 schoolchildren (median age, 13 years) and 786 staff in 11 Tibetan schools. Forty-six TB cases, including 1 with multidrug resistance, were found in schoolchildren, for a prevalence of 853 per 100 000. Extensively drug-resistant TB was diagnosed in 1 staff member. The majority of cases (66%) were subclinical. TBI was detected in 930 of 5234 (18%) schoolchildren and 334 of 634 (53%) staff who completed testing. Children in boarding schools had a higher prevalence of TBI than children in day schools (915/5020 [18%] vs 15/371 [4%]; P < .01). Preventive therapy was provided to 799 of 888 (90%) schoolchildren and 101 of 332 (30%) staff with TBI; 857 (95%) people successfully completed therapy. CONCLUSIONS: TB prevalence is extremely high among Tibetan schoolchildren. Effective active case finding and a high uptake and completion of preventive therapy for children were achieved. With leadership and community mobilization, TB control is implementable on a population level.